Operating mechanism for circuit breakers and the like



INVENTORS STANLEY 7T SCHOF/ELD and S A MUEL H. BODE'N al We.

Filed April 27, 1933 s. T. SCHOFIELD ETAL OPERATING MECHANISM FOR CIRCUIT BREAKERS AND THE LIKE Ban. v22, 1935.

ATTORNEY Patented Jan. 22, 1935 UNITED STATES OPERATING MECHANISM FOR CIRCUI T BREAKERS AND THE LIKE Stanley '1. Schofield, Wilkinsburg, and Samuel H.

.Boden, Turtle Creek, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa... a corporationof Pennsylvania Application April 27, 1933, Serial No. 668,148

19 Claims. (Cl. 200-453) Our invention relates to an operating mechanism for circuit breakers and the like, and it has for an object to provide a mechanism having means for stopping the moving parts with mini mum shock thereto.

A more particular object is to provide a mechanism for effecting quick opening movement of the movable contact and for stopping the same with minimum shock.

In connection with circuit breakers operating at high speed, it is necessary to provide some means for stopping the moving parts without excessive shock in order to avoid damage thereto. This may be done by the use of a dashpot or a 5 spring.v The dashpot is satisfactory for oil circuit breakers, but requires considerable adjustment and maintenance. The usual spring bumper is objectionable in that it causes the contacts to rebound. 7

It is an object of our invention to provide mechanism for stopping moving parts which requires minimum adjustment and maintenance and in which only a slight or minimum amount of rebound is encountered.

In accordance with our invention, we provide an inertia member to which the energy of the moving parts is transferred through a spring, the inertia member being thereby set in-motion. The deflection of the spring is released by the movement of the inertia member, so that there is a minimum or no force to cause the moving parts to rebound. The inertia member strikes against a stationary abutment to absorbthe transferred energy. A relatively weak spring is preferably provided for returning the inertia member to its initial position.

In accordance with our invention, also, the

first spring is used to effect the movement of the movable parts.

The above and other objects are effected by my invention as will be apparent from the following description andclaims taken in connection with the accompanying drawing forming a part of this application, in which:

Fig. 1 is a diagrammatic view, partly in section, showing the contacts of a circuit breaker and the operating mechanism in closed-circuit position;

Fig. 2 is a detail sectional view taken on the line IIII of Fig. 1; and,

Fig. 3 is a detail sectional view taken on the line III-III of Fig. 1.

Referring now to the drawing more in detail, I show stationary contacts 11 and a movable contact or bridging member 12 adapted to'contact 55 withthe contacts 11. The movable contact member 12 is mounted on the end of a lift rod 13, which comprises an insulating part 14, a metal part 15 of smaller diameter, and a connecting member 16- screw-threaded to the upper end of 0 the-part 15. Thelower. end of the connecting part 14 provide shoulders 17 and 18, respectively.

The upper end of the rod 13 is connected through a link 19 to the right hand end of a floating lever 21. 1 e

The lever 21 is pivoted at 22 to a triangular linkage 23, which comprises links 23a, 23b, and 23c. The linkage 23 is pivoted at 24to stationary structure or frame 20, which has pivotpins 24ashown more clearly in Fig. 2. As seen in Fig: 1, the centerline of the'pins 24a coincides with the centerline of a roller 27 mounted on the lever 21, but as shownin Fig.2, the pins 24a' are disposed on opposite sides of the roller 27. The links 23a and 23b arepivoted on the pins 24a, being retained thereon by plates 24?). The1ink= age 23 is adapted to be actuated in clockwise direction from the positionshown on the drawing, by movement of a rod 25 tothe left.

A latch member 26, pivoted on an axis 263, is adapted to retain the left-hand end of the lever 21, the latter being preferably providedwith a roller 27 and adapted to engage with the. latch member. A .spring 27' biases the latch member 26into engagement with the roller 27. A trigger member 28 engages the latch member 26, maintaining the latter in engagement with the roller 2'7. A magnet 29 is adapted to move the trigger member 28 out of. engagement with thelatch member 26. The magnet 29 may be controlled in any desired manner, and maybe responsive to a condition of the circuit controlled by the contacts 11 and 12. The surface of the latch member 26 which is in engagementwith the roller 2'7 extends slightly short of a straight line connecting the axis 26 and the axis or centerof the roller 27, so that, when the trigger member 28 disengages the latch member 26, the latter may be forced to the left, permitting clockwise movement of the lever 21 about the pivot 22.

The mechanism forefiecting the opening movement of the movable contact 12 includes a spring 31, the upper end of which engages a follower 32 and the lower end of which engages a follower 33. In the closed-circuit position shown on the drawing, the follower 32 engages a stationary abutment 34, rigidly connected. to stationary structure indicated diagrammatically at 30,. and the follower 33 engages the shoulder 18 on the lift rod 13, the spring31 being under compression and biasing the movable contact 12 in circuitopening direction. Encompassing therod 13 and the spring 31 is an inertia member 35 having an inwardly extending shoulder 36 which, when the inertia member is in the position shown on the drawing, is adapted to be engaged by the follower 33 when the. deflection of the spring 31 has been substantially released.

A second stationary abutment 36' is also rigidly connected to the stationary structure, asby bolts the stationary abutment 36' and the inertia mem-' ber 35 for the purpose of retaining the latter in its uppermost position and for returning it thereto when it is moved downwardly. The spring 39 need be only strong enough to retain the inertia membenat its uppermost position against the weight of the movable parts. A leather washer 39' is also preferably provided on the lower side of the stationary abutmentv 34. for engagement by the inertia member 35.

The operation of. the above-described mechanism is as follows:

Operation of the mechanism for-effecting quick opening movement of the contact member 12 is initiated by energization of the magnet 29, moving the trigger member 28 to release the latch member 26. Due to the force of the, spring 31 tending to move the lever 21 in clockwise direction, the latch member 26 is moved to the left out of engagement with the roller 27. The spring 31, acting through the follower 33 and the shoulder 18, effects rapid downward movement of the rod 13 and the movable contact 12 to. open the'circuit controlled by the contacts. After. a predetermined movement of the rod 13, preferably at about the point at which the compression of the spring, 31 issubstantially released, the follower 33 strikes the shoulder 36 on the inertiamember 35. The shoulder 18 leaves the follower 33, and the rod 13 and the movable contact 12 continue downward movement unpropelled and unhamvpered for a short distance until the shoulder 17 strikes the follower 32.

The rod and the movable contact are thereafter decelerated, the spring 31 being again compressed by the continued movement, and the force of the spring opposing such further movement. During this decelerating action, the spring is compressed between the rod and the inertia member, the reactive force of the spring being conveyed through the follower 33 to the inertia member 35. The inertia member 35 is thereupon accelerated in downward movement, the kinetic energy of the rod 13 and the movable contact 12 being thereby transferred to the inertia member 35. As the inertia member 35 is accelerated in its downward movement, it begins to release the compression of the spring 31, and preferably its inertia is so chosen that at the moment at which the rod 13 and the contact 12 have been brought toa stop, the compression of the spring 31 is substantially released, or at leastgreatly reduced, so that there is little or no upward rebound of the rod and the, movable contact. For example, the inertia member 35 may weigh lbs.'and the lift rod 13 and the contact 12 may weigh 16 lbs. The downward movement of the inertia member 35 is terminated by abutment against the stationary abutment 36', by means of which the kinetic energy imparted to the inertia member is transferred to and absorbed by the stationary struc- .ture. The spring 39 thereupon moves the in 'ertia member 35 and the movable parts upwardly to normal closed circuit position, in which the inertia member 35 is at the upper end of its travel as'shown on the drawing. I I

To reclose the circuit breaker, the rod 25 is moved to the left, operating the triangular linkage 23 in clockwise direction to lower the piyot .22; The latter moves the lever 21 downwardly the latch member. The rod 25 is thereupon actuated toward the right to raise the pivot 22. The floating lever 21 is thereupon raised about the roller 2'7 as a fulcrum, to move the contact member 12 upwardly to closed circuit position.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various'changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are. imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a shock absorber for stopping the movement of a rapidly moving member, the combination of a'movable inertia element, a spring engageable with said inertia element and with the moving member to transfer the kinetic energy of the movable member to the inertia element for stopping the moving member with minimum shock, and an abutment member, separate from said moving member, adapted to abut the inertia element to stop the same.

2. The combination defined in claim 1 and further including a spring for returning the inertia element to its initial position.

3. In a shock absorber for stopping the movement of a rapidly moving member, the combination of an inertia element, a spring having one end engageable with said inertia element, said parts being so arranged that said moving member engages the other end of said spring to defiect the spring, whereby the kinetic energy of the movingmember is resiliently transferred to the inertia element, and means for stopping the inertia element and absorbing the kinetic energy transferred thereto.

' 4. In a shock absorber for stopping the move ment of a rapidly moving member, the combination of an inertia element, a spring having one end engageable withsaid inertia element, said parts being so arranged that said moving member engages the other end of the said spring to deflect the spring, whereby the kinetic energy of the moving member is resiliently transferred to the inertia element, means for stopping the inertia element and absorbing the kinetic energy transferred thereto, and a spring for biasing the inertia element to its initial position.

5. In a mechanism for rapidly moving and stopping a movable member, a spring operable successively to accelerate said member and thereafter to oppose continued movement of the member, and an inertia element on which is imposed the reactive force of said spring in said opposing action.

6. In a device for accelerating and decelerating a movablemember. the combination of a stationary abutment, an inertia member, and a spring engageable between said stationary abutment and said movable member and adapted, when deflected in such engagement. to effect movement of said movable member, said spring being engageable, upon continued movement of said movable member, between said inertia member and said movable member to decelerate the latter by resiliently transferring the energy of its movement to the inertia -member, thereby stopping the movable member with minimum shock and rebound thereof.

"I. The combination specified in claim 6 and further including a second stationary abutment for stopping the inertia member.

8. A device for accelerating and decelerating a movable member comprising a stationary abutment, a spring adapted to be deflected between stationary abutment, a spring arranged to have one end in engagement with said abutment and the other end in engagement with said movable member and adapted when deflected to accelerate the movable member, an inertia member, said other end of the spring being engageable with said inertia member when the deflection of the spring has been substantially released in accelerating the movable member, the movable member being subsequently engageable with said one end of the spring to decelerate the movable member upon deflection of the spring, the inertia member being movable by the deflection of the spring to release said deflection, thereby avoiding or reducing rebound of the movable member.

10. In a mechanism for rapidly moving and stopping a movable member, the combination of a rod connected to the movable member, a spring, means for engaging one end of said spring with said rod for accelerating the latter, a stationary abutment for retaining the second end of said spring during said accelerating 'action, a movable inertia element engaging said one end of the spring at the termination of said accelerating action, means providing engagement between said rod and said second end of the spring, after the accelerating action, for resiliently terminating the movement of said rod by transferring its kinetic energy to said inertia element.

11. In a mechanism for accelerating and decelerating a movable member, the combination of a rod connected to the movable member, a stationary abutment, a movable inertia element, a spring having one end thereof engageable with said rod in the direction for accelerating said rod and engageable in the same direction with said inertia element after the accelerating action is substantially completed, the other end of the spring being engageable in the opposite direction with said stationary abutment during the accelerating action and thereafter engageable in said opposite direction with said rod for decelerating the same.

12. The combination defined in Claim 11 and further including a second spring for opposing the movement of the inertia member resulting from the decelerating action and for returning the inertia element to its initial position.

13. A device for accelerating and decelerating a movable member comprising a rod connected to the movable member, said rod having oppositely-facing first and second shoulders, a stationary abutment, a spring having its first end engageable with said stationary abutment and its second end engageable with the second shoulder of said rod and adapted, when deflected in such engagement, to accelerate said rod and movable member, an inertia member engageable with said second end of the spring at the termination of said accelerating action, said second shoulder of the rod being subsequently engageable with said first end of the spring to decelerate the rod, the consequent deflection of the spring effecting movement of the inertia member for releasing said deflection whereby rebound of said rod and movable member is avoided.

14. The combination with a movable member, of means for effecting quick translatory movement of the member, a movable mass, elastic means for effecting the transfer of kinetic energy from the member to the mass, and means other than the movable member for taking up the kinetic energy from the movable mass.

15. In apparatus of the character described, a movable member, a spring for effecting quick translatory movement of the member, releasable means for holding the member in a normal position with the spring under deflection, a movable inertia member, and elastic means effective to transmit kinetic energy from the movable member to the inertia member after predetermined movement of the movable member.

16. In apparatus of the character described, a movable member, a spring for effecting quick translatory movement of the member, releasable means for holding the member in a normal position with the spring under deflection, a movable inertia member, and means including said spring for transmitting kinetic energy from the movable member to the inertia member after predetermined movement of the movable member.

17. The combination with a circuit breaker having a movable contact, of means for effecting quick opening movement of said movable contact, a movable inertia member, and elastic means for effecting transfer of kinetic energy from the movable contact to the inertia member.

18. The combination with a circuit breaker having a movable contact, of mechanism providing rapid opening movement and stopping of said movable contact comprising means effecting quick opening movement of said movable contact, a movable inertia. member, and a spring arranged to be operatively interposed between the movable contact and the inertia member to transfer the kinetic energy of the former to the latter.

19. The combination with a circuit breaker having a movable contact, of mechanism providing rapid opening movement and stopping of said movable contact comprising a spring for effecting quick translatory opening movement of said contact, releasable means for holding the contact in closed-circuit position with the spring under deflection, a movable inertia member, and means including said spring for transmitting kinetic energy from the movable contact to the inertia member after a predetermined movement of the movable contact.

STANLEY T. SCHOFIELD. SAMUEL H. BODEN. 

